The present invention is a process whereby aliphatic hydrocarbon rich feed streams containing a mixture of naphthenic hydrocarbons and paraffinic hydrocarbons can be selectively separated into paraffinic rich streams and naphthenic rich streams by a process involving contacting the aliphatic hydrocarbon rich feed stream with one side of a nonselective, porous, partition barrier membrane while simultaneously contacting the other side of the partition barrier membrane with a polar solvent such as ethylene diamine. The naphthenic hydrocarbons selectively and preferentially permeate through the porous, non-selective hydrophobic partition barrier membrane in response to the polar solvent present on the permeate side of said membrane.
The porous partition barrier membrane, although not contributing to the selectivity of the separation process, does prevent or minimize the intermingling of the feed and the selective, polar extraction solvent, intermingling typical of conventional solvent extraction processes. The membrane permits the feed and the polar extraction solvent to share a large contacting surface area while preventing the intermingling of the two streams. The naphthenes selectively permeate through the barrier in response to the polar extraction solvent to produce a naphthenes rich permeate stream.